Concorde wasn’t the first Airliner to Break the Sound Barrier: how the DC-8 became the first commercial transport to go supersonic

The first airliner to go supersonic wasn’t the famous Concorde, which wouldn’t break the sound barrier until an October ’69 test flight, or the Soviet-built Tupolev Tu-144, but rather a humble DC-8.

The DC-8 was the first Douglas jet-powered transport. It entered service simultaneously with United Airlines and Delta Air Lines on Sep. 18, 1959. Powered by four jet turbine engines, the DC-8 was capable of speeds of more than 600 mph (966 km/h). Throughout its 14-year-long production run, the DC-8 went through seven major variants, for a total of 556 aircraft.

On Aug. 21, 1961, a DC-8 even became the first airliner to go supersonic. In fact, it wasn’t the famous Concorde, which wouldn’t break the sound barrier until an October ’69 test flight, or the Soviet-built Tupolev Tu-144, but rather a humble DC-8—no. N9604Z, to be specific.

The test flight was planned by Douglas test pilot William Magruder and was set to take off from Edwards Air Force Base (AFB). As flight test engineer Richard Edwards, told to Air & Space Magazine, the idea was to “get it out there, show the airplane can survive this and not fall apart.” The DC-8, which at the time was competing with the Boeing 707, had been used by commercial carriers for about three years. Even though the DC-8 wasn’t designed to go supersonic, the bragging rights of being the first to do so were worth making the attempt.

In order to reach Mach 1, the jet had to be in a dive. According to Mentalfloss.com, this meant taking it up to 52,000 feet, which was also a record for altitude.

As Edwards tells Air & Space Magazine: “We took it up to 10 miles up…and put it in a half-a-G pushover. Bill maintained about 50 pounds of push. He didn’t trim it for the dive so that it would want to pull out by itself. In the dive, at about 45,000 feet, it went to Mach 1.01 for maybe 16 seconds, then he recovered. But the recovery was a little scary.”

The stabilizer in fact was overloaded and the plane stalled when Magruder tried to pull it back.

“What he did, because he was smart, is something that no other pilot would do,” explains Edwards. “He pushed over into the dive more, which relieved the load on the stabilizer. He was able to run the [stabilizer] motor…and he recovered at about 35,000 feet.” The crew successfully turned a mass-produced airliner into the world’s supersonic commuter jet. (Right by their side the entire time? Chuck Yeager, the first person to ever go supersonic in 1947. He escorted the DC-8 during its test in an F-104.)

“That’s an unofficial supersonic record, payload record, and of course an altitude record for a commercial transport,” Edwards points out.

After the test, DC-8 no. N9604Z was delivered to Canadian Pacific Air Lines and was used by the carrier for almost two decades before being retired. Sadly this piece of aviation history isn’t hanging in a museum somewhere: after it was put out of service in fact, Canadian Pacific sold DC-8 no. N9604Z for scrap.

Photo credit: Douglas and Eduard Marmet via Wikipedia